Database Managment 4) Consider the following requirements for a company database

Question

Database Managment

4) Consider the following requirements for a company database:

A company has employees that have social security number (ssn), salary and phone

Departments are described by a department number (dno), a department name (dname) and budget and are composed of several employees. The company may have several departments by the same name. Employees are not restricted to work in just one department. Departments are managed by a single manager.

Employees have dependents (child) have a name and age. A child must be identified uniquely by name. Assume that name includes first and last name. Assume that only one parent of a child works for the company.

Underline all keys of entity sets

Explanation / Answer

We can design the ER schemas of COMPANY DATABASE in following way.

Primary keys are underlined.

please let me know in case of doubt.

Thanks

1. Employee and Department are strong entity sets.
2. Dependents is a weak entity set.
3. Emp-Child is a identifying relationship.
4. First name and last name is the discriminator key of weak entity set.

Primary keys are underlined.

please let me know in case of doubt.

Thanks

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